Control mechanism for artificial legs



March 23, 1954 E. G. HAAG CONTROL MECHANISM FOR'ARTIFICIAL LEGS I 2 Sheets-Sheet 1 Filed Nov. 19, 1947 March 23, 1954 E. G. HAAG CONTROL MECHANISM FOR ARTIFICIAL-LEGS Filed Nov. 19, 1947 2 Sheets-Sheet 2 INVENTOR.

Patented Mar. 23, 1954 UNITED STATES PATENT OFFICE CONTROL MECHAIIgZLSi FOR ARTIFICIAL 3 Claims.

This invention relates to control mechanism for artificial legs and particularly to the type used when the amputation is above the knee.

The primary object of my invention is the provision of a hydraulic mechanism to be installed inside of an artificial leg, that will prevent the collapse of the leg when bending the knee or when the foot strikes obstructions on the pavement, such as twigs, stones or the like.

Another object is the provision of a mechanism that will allow the user of an artificial leg to have full control overthe leg at all times so that he may walk with'the same ease equal to a natural leg, and wherein there is avoided danger of falling due to failure of the leg to stay rigid when stepping on obstacles or uneven pavements.

A further object is the provision of a hydraulic mechanism for use in artificial legs, adapted for use when the amputation is above the knee, which is controlled by a lever in the artificial foot, affording the user full controlled action of the mechanism, to bend the knee and to kick same in position automatically when the user puts his weight on the leg while walking or standing.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming a part of the specification, with the understanding, however, that therinvention is not to be understood as limited to the exact details of construction shown and described since obvious modifications will occur to a person skilled in the art.

In the drawings:

Figure 1 is a full front elevation of an artificial leg constructed in accordancewith one embodiment of myinvention. V

Figure 2 is a longitudinal section taken substantially on line 22 of Figure 1, and showing the mechanism in relative position to an artificial leg as shown in broken outline.

Figure 3 is a view in side elevation of a second embodiment of my invention.

Figure 4 is a fregmentary longitudinal section of the stop valve and piston structure of the embodiment of Figure 3,-assembled in one housmg. 7

Figure is a sectional view taken substantially on the line 55 of Figure 2.

Referring particularly to Figures 1, 2 and 5 wherein one embodiment of the invention is i1 lustrated it will be noted particularly in Figures -1 and '2 that thedevice employs the transverse toe, heel; knee and thigh pins which are indicated respectively by the reference characters I I. I2,

i3 and I4 and these pins function to secure the mechanism in an artificial leg structure which is shown in broken outline and designated l0, such leg structure being of suitable flexible construction to permit the operation of the mechanism.

The toe pin H extends transversely of and connects together the forward ends of the spaced parallel foot bars l5 which are disposed between and are pivotally mounted for vertical oscillation or swinging, upon the heel pin 12 which couples together the lower ends of the spaced parallel calf bars I6. As shown the lower ends of these calf bars are curved to extend rearwardly slightly, such curved portions being designated I 6 so that the heel pin I2 is rearwardly of the plane of the bars I 6.

Extending transversely between and connecting the foot bars l5 adjacent to but in advance of the heel pin [2, is a cross pin I! which lies in the vertical plane of the spaced calf bars IS.

The cross pin I! is engaged by the lower end of the stem or rod l8 of a diaphragm type pump which is generally designated l9 and which is mounted between the lower ends of the calf bars as shown in Figure 1. The stem l8 of this diaphragm pump is normally urged downwardly by the coil spring 42 so that the diaphragm pump stem or rod l8 constantly engages the pin I! so as to urge the toe of the artificial leg downwardly at all times.

The numeral 20 generally designates a stop cylinder assembly which comprises a piston cylinder 20' mounted upon a supporting pin 2! which is secured to and extends across between the calf bars l6 above the diaphragm foot pump l9. The cylinder is maintained centrally between the calf bars by the spacers 22.

Slidabl'y positioned within the cylinder is a piston 23 to which is fixed the piston rod 24 which extends upwardly beyond the upper ends of the calf bars l6 and is pivotally coupled at its upper end with a cross pin 25.

The numeral 26 designates two spaced parallel thigh bars which at their lower ends are of increased width as indicated at 26' and the forward ends of the portions 26' of the thigh bars have therein the elliptical openings 21 through which the knee pin l3 passes. This pin I3 is rigid with the upper end of the calf bars [6 but is adapted to have slight vertical movement in the elliptical openings-'21 of the thigh bars so that the calf portion of-the' artificial leg may move up and 'down slightly for the correct operation of the mechanism.

construction here being such that the high bars can be made considerably shorter.

It will be readily apparent that this second embodiment of the invention will be mounted within an artificial leg in substantially the same manner as the first described embodiment, use being made for this purpose of the transverse pins Ilia, l2a, I 3a. Foot bars l5a are mounted for vertical oscillation on the pin l2a. and the lower ends of the calf bars l6a are rearwardly curved as indicated at I6b whereby to properly position the connecting pin Ila for engagement by the pump rod 18a of the diaphragm pump l9a. At the upper ends of the calf bars lGa the forwardly curving lower ends of the thigh bars 26a position between the calf bars Ilia and are pivotallymounted upon the pin l3a.

In this embodiment the stop cylinder and the stop regulating valve are assembled as a unit which is generally designated 20a and is mounted between the calf bars Ilia upon the supporting pin 2 l a. This unit is formed to provide the piston cylinder 43 which opens upwardly to receive the piston 23a, the upper end of which is pivotally coupled with the pin 25a which connects across between the thigh bars 2611.

Also formed in the unitary body 20a is a chamber 55 which is adjacent to and parallels the piston cylinder 43 and in which chamber 55 is slidably mounted the needle valve piston which carries the upper and lower needle valves 48 and 41 respectively on the ends of the upwardly and downwardly extending stems 46a and 41a.

Paralleling the cylinder 43 is a fluid passage 51, the lower end of which communicates with the lower end of the cylinder as shown and also communicates with the passage 54 which leads upwardly into the chamber 54a into which the valve needle 41 moves in opening. The upper end of the passage 51 communicates with the port 46b 4 which is closed by the upper needle valve 46 when it moves upwardly or to closing position.

Housed in the chamber 55 above the valve piston 45, is a spring 56 which engages the piston 45 and normally urges the same downwardly thus constantly tending to move the valve needle 46 to open position and the valve 41 to closed position.

The fluid tank or receptacle 36a is mounted upon the thigh bars 26a and the lower part of this tank has connected therewith the tube 49 which opens into the upper part of the chamber 55 above the valve piston 45 but below the inlet port 46b. From the lower part of the chamber 55, below the valve piston 45, an end of a tube 48 leads downwardly to the outlet side of the diaphragm pump l9a. This tube has therein the upwardly opening check valve 48a which permits fluid to pass only from the diaphragm pump upwardly and into the lower part of the piston chamber 55.

The tube 48 is also in communication with the chamber 54a with which the passage 51 is in communication when the valve needle 41 is raised or in open position, this communication between the chamber 54a and the tube 48 being by means of the connecting nipple 54b.

Connected at one end with the upper part of the tank 36a is the fluid suction line which leads downwardly and opens at its opposite end into the other side of the diaphragm pump l9a through a downwardly opening check valve 54a. Above the check valve 50 a coupling nipple 50b leads from the pipe lineor tube50 into the lower part of the stop cylinder 43 and above this nipple the pipe line- 50 has a downwardly opening check valve 5| therein. 7 1

Connecting the upper end of the tube 48 with thelower end of the tube 49 is avalve shunt tube 52 in which is locateda valve 53 of the same type as the valve 4| a, to be manually controlled by the user of the mechanism to facilitate bending the artificial leg at the knee when the wearer desires to sit down. The numeral 53a designates the flexible control cable by which the manual valve 53 is actuated.

While the mechanism is slightly different in this second embodiment of the invention the operation of the same is essentially the same as that of the first embodiment, such operation being, however, entirely through the medium of the foot bars l5a.

The valve 53 is normally closed and when pressure is applied to the foot bars l5a the diaphragm of the pump 1 9a will be compressed to eject fluid upwardly through the tube 48 into the chamber 55 below the valve piston 45 thus raising the piston and closing the port 46b by means of the valve 46. This will open the valve needle leading to the passage 54 and fluid may pass into the lower part of the piston cylinder 43. It will thus be seen that full weight may be applied upon the mechanism since downward pressure to the piston 23a in the cylinder 43 will fail to eject any fluid from the cylinder due to the fact that the port 46 is closed. Thus desired upward thrust will be applied to the thigh bars 26a and the knee joint will be locked.

When the user of the mechanism desires to sit down thus requiring the release of the piston 23a so that the thigh bars 26a can swing down on the pivot pin 13a, the control valve 53 is opened thus permitting the fluid to pass from the cylinder 43 through the passage 54 into the upper end of the pipe line 48 and then through the shunt line 52 to th line 45 which returns the fluid to the tank 35-01.

After the user of the mechanism has taken a step to thereby lock the piston 23a in its raised position, when the leg is lifted the fluid in the cylinder 43 passes out into the lower part of the suction line 50, flowing back to the pump [9a. This flow takes place as a result of the action of the spring I 8a forcing the foot bars l5a downwardly thus relieving the pressure upon the diaphragm of the pump Ma and creating a reduced pressure in the pump chamber. The movement of the fluid out of the cylinder 43 reduces the fluid pressure by way of the nipple 54b and the passage 54, in the lower part of the chamber 55 beneath the valve piston 54 thus allowing the needle valve 46 to open. The kne joint is now free to function for the bending of the leg and downward movement of the piston 23a will cause the fluid to pass back to the tank 36a by way of the passage 5'! and the port 461). When the foot is again placed on the ground and the foot bars |5a are forced upwardly the same locking action of the piston 23a will occur and these actions will continue to alternate during the walking movements of the wearer.

It will be seen from the foregoing that the mechanism of the present invention as illustrated in the two embodiments shown, is of relatively simple character and will function smoothly and rapidly to permit the amputee to walk, stand or sit down or execute other movements of the leg which are permitted with the normal leg. At the "same time there are no small, delicate parts to get out of adjustment or parts requiring frequent 7 edjustmentdoi thmproper operation-of the device.

11 1 1 19.;- v V .u An artificial leg control mechanismdesigned for installation 3111" an artificial ileg body, comprising a; thigh portion a knee joint pin carried by-the thigh portion-, a;- relatively long calf portion-pivotallyjmounted at on -end uponsaid pin, an-ank-le pin carried. at the other-end ofthe calfportion, -a= foot partepivotally mounted upon said ankle pin, said knee joint pin-and thigh: portion being --loosely}eoupled together to form 9a lost motion jointbetween the thigh and calf portions :whereby the calf portion i has a slight fre reotilinear movement relative; to the thigh portion, a brace element connected between the; thigh and calf portions across the knee joint, said brace element comprising a fluid cylinder, a piston in thepylinderancl a piston rod extending outwe rdly-35mm the cy l-incler, a fiuid receptacle carried byonepfsaid portions,'means for conducting fluid from the receptacle into said cylinder beneath-thepistom-a fluidli-ne leading from the cylinder from beneath the piston back to the receptacle, valve means carried by the thigh portionfor closing said fiuid-line, and an operative :couplingbetween-said valve meansand the calf portionoperatingto close thevalve means upon rectilinearmovement of thecalf portion in'one r t on 1 -2.'=An=artificial--leg control mechanism of the character stated -yin 16181311 1, wherein the said meansfor transterring fluidfromthe receptacle .to -the;cy-l inder beneath the piston includes a pump carried -;by;-a.portionof the mechanism, and an operative coupling between the pump and the foot eportion forefiectingthe operation of the pump upon actuation of the foot portion on the-anklejointpin,

3. An artificial leg control-mechanism of the character stated iii-claim 1, wherein the said meansfor, transferring-fluid from the receptacle to the cylinder beneath theepiston includes a pump carried by a portionof the mechanism, and anoperative coupling'ebetween the pump and the foot portion for effecting-the operation of thelpump upon actuation of the-foot-portionon the ankle joint pin, a fluid shunt line connected across th e valve f in the line -.-leading from 4 the piston cylinder-back -to the receptacle, and a manually-controlledvalve inthe fluid shunt line.

EMIL GEORGE I-IAAG.

References Cited in the file of this patent UNITED 'STATESPATENTS Number Name Date 2,478,? 21 Stewart Aug; 9, 1949 FOREIGN PATENTS Nun-ricer 7 Country Date 25,532 "France Dec; 28,1922 

